Knob



FIG. 1 is a front view of a knob showing my new design;

FIG. 2 is an enlarged right view thereof, the left side being a mirror image;

FIG. 3 is an enlarged bottom plan view thereof; the top plan view being a mirror image; and,

FIG. 4 is a rear view thereof. 

The ornamental design for a knob, as shown and described. 